1. Field of the Invention
The present invention relates to the gearing associated with an engine starter and more particularly it relates to starter gearing of the positive shift type that includes clutch teeth to provide driving as well as overrunning features. The clutch teeth are separated under the influence of radially movable flyweight members, the movement of which is circumferentially restricted by guide members.
2. Description of the Prior Art
The present invention is an improvement over the starter gearing system shown and described in U.S. Pat. No. 4,611,499 entitled "Engine Starter Gearing" and issued Sept. 16, 1986. The above referenced patent disclosed engine starter gearing that utilized centrifugal weights and a conical thrust washer for separating the dentil clutch teeth after engine start-up, thus, preventing long periods of clutch overrunning and accompanying undesirable wear on the clutch teeth. An annular recess is formed in the driven clutch member. An annular recess is also provided in the face of the driving clutch member facing the driven clutch member. An annular thrust washer is fitted in the annular recesses of the driven and driving clutch members and abuts the driving clutch member. A conical surface is provided on the annular thrust washer facing the driven clutch member. A plurality of arcuately spaced centrifugal weight members are provided in the annular recess of the driven clutch member. The centrifugal weight members are provided with an inclined surface that cooperates with the conical surface of the annular thrust washer. When an overrunning condition occurs, the centrifugal weight members move radially outward and the inclined surfaces of the weight members engage the conical surface of the annular thrust washer so as to urge the driving clutch member away from the driven clutch member to disengage the clutch teeth. The centrifugal weight members are prevented from axial or rotational movement relative to the driven clutch member by an integrally formed radially aligned pin associated with each of the movable weight members. In another embodiment of the invention, the pin is dispensed with and the weight members are restricted in axial and circumferential movement relative to the driven clutch member by guide surfaces that are an integral part of the clutch members.
While the engine starter device described above has been satisfactory in operation, it required centrifugal weight members that were expensive to manufacture in the embodiment equipped with integral pins. In the pinless embodiment, the centrifugal weight member guides required internal machining which is always expensive and fraught with tolerance problems.
Thus, it becomes highly desirable to build an improved engine starting device that retains the ease of rapid assembly plus proven economies in manufacture of the individual components thereof.